Jean Pierre Clément Marie d'Orléans, Duc de Guise (September 4, 1874-August 25, 1940) was the son of Prince Robert d'Orléans, and great-grandson of Louis Philippe I, King of the French. Upon the death of his cousin the Comte of Paris, claimant to the throne of France as Philip VIII, the Duc de Guise became, at least for his Orleanist supporters, titular king of France as Jean III. The title was disputed by members of the Spanish Anjou branch of the family, descended from Louis XIV.
In 1899, Jean d'Orléans married his cousin Isabelle d'Orléans (1878-1961). They had four children.
After the comte de Paris' death in 1894 Gaston tried again, and the comte de Paris' son and successor as head of house made clear in a document of 15 July 1901 that this was not possible.
He was born to Henri, Comte de Paris and his wife Isabelle of Orleans-Braganza in Woluwe-Saint-Pierre, Belgium, because an 1886 law banned the heirs of formerly reigning French dynasties from entering France.
Jean (born 1965), Duke of Vendôme and Dauphin de Viennois, unmarried.